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CONNECTICUT 


Con  i 

S 


Agricultural  Experiment  Station  ^°-^ 


NEW^  HAVEN,   CONN. 


BULLETIN  216 


DECEMBER,  1919 


ENTOMOLOGICAL  SERIES,   No.  27. 


INSECTS  ATTACKING  SQUASH,  CUCUMBER,  AND 
ALLIED  PLANTS  IN  CONNECTICUT. 


By  W.   E.   Brixton. 


CONTENTS 


Page 

Officers  and  Staff  of  Station  ....  32 
Insects    Attacking    Squash,    Cu- 
cumber and  Allied   Plants  in 

Connecticut 33 

Key    to     Insects    of     Squashes, 

Pumpkins,  etc 33 

Chewing  Insects 34 

Striped  Cucumber  Beetle 34 

Twelve-spotted  CucumberBeetle  37 

Garden  Flea  or  Springtail 37 


Page 

Cucumber  or  Potato  Flea  Beetle  38 

Squash-vine  Borer 39 

Squash  Lad3'-Beetle 42 

Other  Chewing  Insects 43 

Sucking  Insects 44 

Squash  Bug 44 

Melon  Aphid 47 

Squash  Aphid 49 

Greenhouse  White-Fly 50 

Summary 50 


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  of  Connecticut  who 
apply  for  them,  and  to  others  as  far  as  the  editions  permit. 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION. 

OFFICERS  AND  STAFF 
December,  1919. 


BOARD  OF  CONTROL. 
His  Excellency,  Marcus  H.  Holcomb,  ex-officio.  President. 

James  H.  Webb,  Vice  President Hamdeti 

George   A.    Hopson,   Secretary New  Haven 

E.  H.  Jenkins,  Director  and  Treasurer New  Haven 

Joseph  W.  Alsop Avon 

Charles  R.  Treat Orange 

Elijah  Rogers  Southington 

William  H.  Hall South  Willington 


Administration. 


Chemistry. 

Analytical  Laboratory. 


Protein  Research. 
Botany. 


Entomology. 

Forestry. 

Plant  Breeding. 
Vegetable  Growing. 


STAFF. 
E.  H.  Jenkins,  Ph.D.,  Director  and  Treasurer. 
Miss  V.  E.  Cole,  Librarian  and  Stenographer. 
Miss  L.  M.  Brautlecht,  Bookkeeper  and  Stenographer. 
William  Veitch,  In  charge  of  Buildings  and  Grounds. 

E.  Monroe  Bailey,  Ph.D.,  Chemist  in  Charge. 

R.  E.  Andrew.  M.A.,  C.  E.  Shepard,    )^^,^j^„j  Chemists. 

H.  D.  Edmond,  B.S.  ' 

Frank  Sheldon,  Laboratory  Assistant. 

V.  L.  Churchill,  Sampling  Agent. 

Miss  A.  H.  Moss,  Clerk. 

T.  B.  Osborne,  Ph.D.,  D.Sc,  Chemist  in  Charge. 

G.  P.  Clinton,  Sc.D.,  Botanist. 

E.  M.  Stoddard,  B.S.,  Assistant  Botanist. 

Miss  Florence  A.  McCormick,  Ph.D.,  Scientific  Assistant. 

G.  E.  Graham,  General  Assistant. 

Mrs.  W.  W.  Kelsey,  Stenographer. 

W.  E.  Brixton,  Ph.D.,  Entomologist:    State  Entomologist. 

B.  H.  Walden,  B.Agr.,  I.  W.  Davis,  B.Sc,  i  Assistant 

M.  P.  Zappe,  B.S.,  Philip  Garman,  Ph.D.,    >   Entomologists. 
K.  F.  Chamberlain,  ' 

Miss  Gladys  M.  Finley,  Stenographer. 

Walter  O.  Filley,  Forester,  also  State  Forester 

and  State  Forest  Fire  Warden. 
A.  E.  Moss,  M.F.,  Assistant  State  and  Station  Forester. 
Miss  E.  L.  Avery,  Stenographer. 

Donald  F.  Jones,  S.D.,  Plant  Breeder. 

C.  D.  Hubbell,  Assistant. 

W.  C.  Pelton,  B.S. 


Insects  Attacking  Squash,  Cucumber  and 
Allied  Plants  in  Connecticut. 

By  W.  E.  Britton,  Entomologist. 

A  paper  on  this  subject  was  published  in  the  report  of  this 
Station  for  1908,  page  805,  but  it  has  long  been  out  of  print. 
The  present  paper  follows  the  plan  of  the  earlier  one,  but  has 
been  revised,  enlarged,  and  wholly  rewritten,  and  is  published 
in  this  form  so  that  the  information  can  be  placed  in  the  hands  of 
truck  crop  growers  throughout  the  state. 

For  the  past  five  years,  cucurbitaceous  plants  have  been  grown 
each  year  at  the  Station  farm  at  Mount  Carmel  for  the  purpose 
of  studying  the  insects  attacking  them  and  methods  of  control. 
Consequently  this  paper  is  more  than  a  compilation,  and  embodies 
the  results  of  our  own  experiments  and  experience. 

Cucumbers,  squashes,  pumpkins  and  melons  are  grown  rather 
extensively  in  Connecticut,  and  are  attacked  and  often  severely 
injured  by  a  number  of  insect  pests.  For  the  hasty  identification 
of  these  insects  the  reader  is  referred  to  the  following  key  revised 
from  the  earlier  paper  mentioned  above : — 

KEY  TO  INSECTS  OF  SQUASHES,  PUMPKINS,   CUCUMBERS 
AND  MELONS. 

Boring  in  the  roots  and  stem —  ^^^^ 

Small,  slender  larvae  tunneling  in  the  main  root  or  stem  below 
ground 

Striped  cucumber  beetle,  Diabrotica  vittata    34 
Large,  stout  larvae  boring  in  squash  stems  above  ground 

Squash  vine  borer,  Melittia  satyriniformis    39 
Devouring  the  stem  and  leaves — 

Small  (1.2  mm.)  purplish  jumping  springtails 

The  garden  flea  or  springtail,  Sminthurus  hortensis    37 
(2  mm.)  black  jumping  beetles  feeding  upon  the  young  leaves 

Cucumber  flea  beetle,  Epitrix  cucumeris    38 
Larger    (5-7    mm.)    yellowish    beetles    feeding   upon    the    leaves. 
Body  yellow,  marked  with  three  longitudinal  black  stripes 

Striped  cucumber  beetle,  Diabrotica  vittata    34 
Body  greenish  yellow,  marked  with  twelve  black  spots 

Twelve-spotted  cucumber  beetle,  Diabrotica  xii-punctata    37 
Large  (8-10  mm.)  hemispherical  beetle,  orange,  marked  with  black 
spots,  or  yellow  larva  with  black  spines 

Squash  lady-beetle,  Epilachna  borealis    42 


34 


CONNECTICUT   EXPERIMENT    STATION    BULLETIN   2l6. 


Sucking  sap  from  the  under  side  of  the  leaves — 

Small  dark  green  or  brownish  plant  lice,  often  very  abundant 

Melon  aphid  Aphis  gossypii    47 
Larger  bright  green  plant  lice  usually  not  abundant 

Squash  aphid,  Macrosiphum  cucurbitae    49 
Grayish-brown  bug  with  spicy  odor  (15  mm.  when  full-grown) 

Squash  bug,  Anasa  tristis    44 
Small  greenish-white  scale-like  insects  on  the  under  leaf  surface 
of  plants  growing  under  glass  or  near  greenhouses.     Pure- 
white  moth-like  adults  resting  on  the  leaves,  and  flying  about 

Greenhouse  white-fly,  Asterochiton  vaporariorum    50 


CHEWING  INSECTS. 

The  Striped  Cucumber  Beetle. 

Diahrotica  vittata  Fabr. 

As  soon  as  the  plants  appear  above  the  surface  of  the  ground, 
and  sometimes  before,  they  are  attacked  as  shown  on  plate  I,  c, 
by  small  beetles,  striped  lengthwise  with  yellow  and  black.    These 


Figure  7.  The  striped  cucumber  beetle :  a,  adult  beetle ;  b,  larva ;  c, 
pupa;  d,  side  view  of  anal  segment.  All  greatly  enlarged.  (After  Chit- 
tenden, Circular  31,  Bureau  of  Entomology,  U.  S.  Department  of  Agri- 
culture.) 


beetles  eat  away  the  tender  tissue  of  seed  leaves  and  young 
stems,  often  killing  the  plants  unless  treatment  is  given.  They 
are  about  one-fifth  of  an  inch  (5  mm.)  in  length,  with  thorax  and 
wing-covers  yellow,  with  head  and  three  longitudinal  stripes, 
black.     See  figure  7,  and  plate  I,  b. 


SQUASH   AND   CUCUMBER   INSECTS.  35 

At  the  time  the  beetles  are  feeding  they  are  also  mating  and 
the  females  lay  eggs  around  the  stem,  just  below  the  surface 
of  the  ground.  These  eggs  are  shown  on  plate  I,  a.  The  larvae 
hatching  from  them  are  slender  whitish  grubs  with  black  heads, 
which  tunnel  in  the  roots  or  main  stem  in  the  ground,  sometimes 
causing  considerable  injury,  as  shown  on  plate  II,  though  prob- 
ably this  injury  is  less  than  that  caused  by  the  adults.  The  tun- 
nels afford  entrance  for  the  wilt  diseases  which  are  often  serious. 
The  white  pupa  stage  lasts  about  a  week  and  occurs  in  the  ground. 
There  are  two  generations  each  year  in  the  South,  but  only  one  in 
Connecticut,  and  the  winter  is  passed  by  the  adult  beetles  in  the 
ground.  Late  in  the  summer  the  beetles  are  often  abundant 
and  feed  upon  the  flowers  of  squashes  and  cucumbers  and  also 
upon  goldenrod  and  other  native  flowers.  They  are  often  found 
resting  in  the  curled  leaves  of  the  old  vines. 

One  parasite,  a  Tachinid  fly,  Celatoria  diabroticae  Shimer, 
has  been  reared  from  the  striped  cucumber  beetle  in  California 
and  Texas. 

METHODS   OF   CONTROL. 

Control  methods  in  vogue  against  this  insect  may  be  classified 
as  follows : — 

(i)  Cultural  practices. 

(2)  Covering  the  plants. 

(3)  Applying  poisons  or  repellents, 

(i)  Cultural  practices  consist  of  crop  rotation,  the  use  of 
quick-acting  fertilizers  to  force  plant  growth,  plowing,  destroy- 
ing old  vines,  time  of  planting,  and  the  use  of  trap  crops.  Some 
of  these  need  no  explanation.  It  is  advisable  where  possible,  to 
plant  the  seeds  in  berry  baskets  or  paper  pots  under  glass  and 
set  them  in  the  field  when  they  are  five  or  six  inches  tall  as  they 
are  not  so  liable  to  be  destroyed.  Deep  plowing  in  the  spring 
will  expose  many  hibernating  adults  which  may  be  killed  before 
they  have  a  chance  to  attack  the  vines.  As  soon  as  the  crop  has 
been  harvested  in  the  fall,  the  vines  should  be  gathered  and 
burned  to  kill  the  insects  resting  on  them.  A  light  harrowing  of 
the  ground  immediately  afterwards  will  kill  many  of  them. 

Trap  crops  of  squash  or  beans  may  be  planted  early  around 
the  field  to  attract  the  beetles.    These  can  then  be  poisoned  and 


36  CONNECTICUT   EXPERIMENT   STATION    BULLETIN   2l6. 

many  of  the  beetles  will  be  killed  before  the  regular  crop  is  ready 
to  be  attacked. 

(2)  The  hills  may  be  covered  with  plant  protectors  of  wire  cloth 
or  cheese  cloth  to  keep  the  beetles  away  from  the  plants.  Cloth 
covered  protectors  are  for  sale  on  the  market,  or  may  be  made  at 
home  by  cutting  a  barrel  hoop  in  two  equal  parts  and  fastening 
the  centers  of  the  two  pieces  together  at  right  angles,  setting  the 
ends  in  the  ground  and  covering  with  cheese  cloth  or  mosquito 
netting.  Still  better,  fasten  the  ends  of  the  semicircular  pieces 
to  another  hoop  lying  horizontally  and  cover  the  whole  with 
netting  to  make  a  portable  frame  protector.  As  soon  as  the 
plants  fill  the  protectors,  the  protectors  may  be  removed  and 
stored,  for  the  following  season.  The  cloth  will  usually  last  about 
two  years,  possibly  three,  then  the  frames  will  need  recovering. 
It  is  often  necessary  to  mend  or  patch  the  netting  when  small 
holes  get  torn  in  it.  Boxes  and  various  other  forms  of  wood 
and  netting  may  be  adapted  for  service  as  plant  protectors,  but 
they  are  for  use  in  the  home  gardens. 

All  forms  of  plant  protectors  must  be  placed  over  the  hills 
before  the  beetles  appear.  Factory-made  protectors  are  shown 
on  plate  III,  c. 

(3)  Most  commercial  growers  apply  poison  to  the  young  plants 
as  a  protection.  Lead  arsenate  is  perhaps  the  best  for  this  pur- 
pose, and  it  may  be  used  as  a  spray  or  as  a  dry  powder.  The 
beetles  do  not  like  to  come  out  of  the  ground  through  a  layer 
of  dry  powder,  and  a  heavy  application  of  dry  arsenate  of  lead 
is  usually  effective.  If  the  plants  are  sprayed,  it  is  essential  that 
the  under  surface  of  the  leaves  be  coated  or  the  beetles  will  con- 
gregate there  and  eat  away  the  substance  of  the  plant.  Where 
cucumbers  are  grown,  it  is  advisable  to  spray  them  with  Bordeaux 
mixture  to  which  lead  arsenate  may  be  added  at  the  rate  of  two 
ounces  of  the  paste  or  one  ounce  of  the  dry  powder  to  one  gallon 
of  the  liquid. 

Various  other  dry  powders,  such  as  air-slaked  lime,  gypsum 
or  land  plaster,  and  soot,  freely  dusted  upon  and  around  the  plants 
are  of  considerable  value  in  controlling  the  striped  cucumber 
beetle. 


squash  and  cucumber  insects.  37 

The  Twelve-Spotted  Cucumber  Beetle,  or  Southern 
Corn  Root  Worm. 

Diabrotica  xii-punctata  Oliv. 

Though  having  a  long  list  of  food  plants,  including  nearly  all 
of  the  common  vegetables,  and  not  usually  considered  as  a  par- 
ticular pest  of  cucurbitaceous  plants,  it  has  been  so  abundant  in 
certain  fields  in  some  seasons  that  considerable  damage  must 
have  resulted  from  it.  In  the  South,  the  larvae  are  a  serious 
pest  of  corn  roots,  and  it  is  called  the  corn  root  worm.  It  also 
attacks  rye,  millet,  and  garden  beans,  often  doing  considerable 
damage. 

The  adult  beetle  shown  on  plate  III,  a,  is  somewhat  larger 
and  stouter  than  the  striped  cucumber  beetle,  and  averages  about 
7  mm.  in  length.  The  wing-covers  are  greenish-yellow,  marked 
with  twelve  black  spots  varying  in  size  and  arranged  in  three 
transverse  rows.  The  thorax  is  bright  yellow  and  the  head 
black.  The  legs,  except  basal  half  of  thighs,  and  the  antennae 
are  blackish ;  basal  half  of  thighs  greenish-yellow. 

The  life  history  is  similar  to  that  of  the  striped  beetle,  each 
female  laying  two  or  three  hundred  eggs  in  the  soil.  These  eggs 
hatch  in  from  one  to  three  weeks,  and  the  larvae  tunnel  in  the 
roots  of  corn  and  other  plants,  becoming  mature  in  from  two  to 
five  weeks :  then  they  pupate  in  earthen  cells  in  the  ground,  the 
beetles  emerging  a  week  or  two  later. 

When  abundant  this  insect  can  be  controlled  in  the  same  manner 
as  the  striped  cucumber  beetle. 


The  Garden  Flea  or  Springtail. 
Sminthurus  hortensis  Fitch. 

Small  seedling  plants  of  many  kinds  are  occasionally  injured 
by  very  small  jumping  flea-like  purplish  insects  which  swarm 
in  the  soil  and  eat  small  holes  in  the  leaves  and  stems,  sometimes 
killing  the  plants.  If  the  plants  reach  several  inches  in  height 
and  produce  their  second  leaves,  they  will  not  be  injured  by  these 
springtails. 

The  garden  flea  or  springtail  is  about  one-twentieth  of  an  inch 
long,  dark  purple  with  pale  yellow  spots,  and  at  the  tip  of  the 


38  CONNECTICUT   EXPERIMENT    STATION    BULLETIN    2l6. 

abdomen  there  is  borne  a  peculiar  forked  appendage  by  means 
of  which  it  jumps. 

This  is  one  of  the  lowest  forms  of  insects,  and  is  very  abundant 
for  two  or  three  weeks  just  as  the  seedlings  are  coming  up. 

Dusting  with  insect  powder  or  ground  tobacco  is  suggested 
as  a  remedy.  Spraying  with  nicotine  would  doubtless  kill  great 
numbers  of  the  springtails. 

The  Cucumber  or  Potato  Flea-Beetle. 
Epitrix  cucumeris  Harris. 
The  seedling  plants  of  cucumbers  are  often  attacked  and 
injured  by  a  small  black  jumping  beetle  which  eats  holes  in  the 
leaves.  This  is  the  same  pest  that  commonly  injures  potato, 
tomato,  egg-plants  and  tobacco  in  Connecticut  fields  and  is  shown 
in  figure  8.  It  is  about  one-sixteenth  of  an  inch  in  length,  legs 
and  antennae  are  yellowish,  wing-covers  and  thorax,  jet  black. 


FiGXJRE  8.  The  cucumber  flea  beetle  Epitrix  cucumeris,  greatly  enlarged. 
(After  Chittenden,  Bureau  of  Entomology,  U.  S.  Department  of  Agri- 
culture.) 

The  adult  beetles  live  through  the  winter  under  leaves  and 
rubbish  and  the  eggs  are  laid  in  May  and  June.  The  larvae  are 
white  thread-like  worms  which  feed  upon  roots  and  therefore 
live  and  transform  beneath  the  surface  of  the  ground.  Probably 
there  are  two,  and  possibly  three,  generations  each  year. 

Flea  beetles  may  be  killed  by  arsenical  sprays ;  driven  away 
by  repellents ;   or  trapped  by  mechanical  devices. 

Ordinarily  the  application  of  lead  arsenate  to  control  the  striped 
cucumber  beetle  will  also  control  flea-beetles.    Bordeaux  mixture 


SQUASH    AND    CUCUMBER    INSECTS.  39 

is  recognized  as  a  repellent  by  gardeners,  and  may  well  be 
applied  with  the  lead  arsenate  as  it  is  needed  to  control  certain 
fungous  diseases  and  should  be  sprayed  against  both  upper  and 
under  surfaces  of  the  leaves. 

Insect  powder,  one  pound  in  ten  gallons  of  water,  or  lead 
arsenate  mixture  in  which  gelatine  has  been  incorporated  gave 
the  best  results  in  tests  in  1914  at  the  New  Jersey  Station.* 

For  controlling  flea-beetles  on  potatoes.  Prof.  C.  L.  Metcalf 
devised  a  sticky  box  or  trap  which  has  been  described,!  but 
which  is  hardly  necessary  to  consider  in  connection  with  cucurbi- 
taceous  plants.  The  application  of  lead  arsenate  will  usually  be 
found  sufficiently  effective. 

The  Squash-Vine  Borer. 

Melittia  satyriniformis  Hubn. 

With  the  possible  exception  of  the  striped  cucumber  beetle, 
which  is  occasionally  very  destructive,  the  squash-vine  borer  is 
the  most  important  pest  of  squashes  and  pumpkins  in  Connect- 
icut. This  insect  causes  the  vines  to  wither  in  July  and  August, 
and  to  die  before  maturing  their  crop.  Cucumbers  and  melons 
are  seldom  attacked  if  squashes  and  pumpkins  are  plentiful  in 
the  neighborhood. 

The  larva  or  borer  tunnels  in  the  main  stem  near  the  surface 
of  the  ground  as  shown  on  plate  IV,  and  decay  sets  in  often 
involving  the  whole  stem  which  frequently  becomes  entirely 
severed,  thus  shutting  off  the  supply  of  sap  to  the  plant.  The 
wilting  is  usually  the  first  sign  of  attack,  though  an  earlier 
examination  would  show  the  yellow  pellets  of  frass  or  excrement 
which  are  thrown  out  of  holes  in  the  stem. 

The  adult  is  one  of  the  clear-wing  or  Sesiid  moths  having  a 
wing-spread  of  from  one  to  one  and  one-fourth  inches.  The 
fore  wings  are  opaque  dark  olive-green  with  a  metallic  luster  and 
a  fringe  of  brownish-black.  The  rear  wings  are  transparent 
with  a  bluish  reflection,  and  veins  and  fringe  are  black.  The 
thorax  and  antennae  are  colored  about  like  the  fore  wings,  with 


*  Report  New  Jersey  Agricultural  College  Experiment  Station  for  1914, 
page  378. 

t  Journal  of  Economic  Entomology,  Vol.  8,  page  240,  1915 :  Report 
Conn,  Agr.  Expt.  Station  for  1918,  page  105. 


40 


CONNECTICUT    EXPERIMENT    STATION    BULLETIN    2l6. 


abdomen  reddish-brown,  legs  bright  orange  and  tarsi  black  with 
white  bands.  When  at  rest  the  wings  are  folded  horizontally  as 
shown  in  figure  9,  b. 

The  egg  is  about  one  millimeter  in  diameter,  oval  in  outline, 
flattened  at  the  point  of  attachment,  and  is  dull  red  in  color.  The 
female  may  lay  two  hundred  or  more  eggs,  and  at  first  these 
are  deposited  singly  on  the  stem  of  the  vine  near  its  base  during 
June  or  early  July  in  Connecticut.  Later  in  the  season,  the  eggs 
may  be  laid  at  almost  any  point  on  the  plant  and  the  borers  are 
often  found  in  the  leaf  petioles.     From  six  to  fifteen  days  are 


Figure  9.  The  squash  borer :  a,  male  moth ;  b,  female,  with  wings 
folded  as  when  at  rest;  c,  eggs  on  section  of  squash  stem;  d,  full-grown 
larva  in  the  stem ;  e,  pupa ;  /,  pupal  cell.  All  one-third  larger  than 
natural  size.  (After  Chittenden,  Circular  38,  Bureau  of  Entomology, 
U.  S.  Department  of  Agriculture.) 


required  for  the  eggs  to  hatch  and  the  young  larvae  enter  the 
stem  and  begin  their  depredations,  usually  working  toward  the 
root,  but  frequently  going  in  the  opposite  direction.  Later  in  the 
summer  the  larvae  may  be  found  tunneling  in  all  parts  of  the 
stem,  leaf  petioles  and  even  in  the  fruit.  The  mature  larva  is 
a  fat  white  grub,  with  black  head,  and  is  about  an  inch  in  length. 
When  ready  to  transform  it  goes  into  the  ground  one  or  two 
inches  below  the  surface,  and  spins  a  tough  brownish  cocoon, 
into  the  outer  layer  of  which  particles  of  soil  are  fastened.  This 
cocoon  is  about  three-fourths  of  an  inch  long.  In  Connecticut 
the  caterpillars  remain  in  their  cocoons  until  the  following  season. 


SQUASH    AND    CUCUMBER    INSECTS.  4I 

There  are  two  broods  in  the  South  but  only  one  in  Connecticut. 
Between  the  latitudes  of  Long  Island  and  Washington,  D.  C, 
there  is  a  partial  second  brood. 

The  pupa  is  about  five-eighths  of  an  inch  in  length,  is  dark 
brown,  and  its  head  bears  a  sharp  horn-like  projection  by  means 
of  which  it  cuts  its  way  out  of  the  cocoon. 

This  insect  occurs  throughout  the  eastern  half  of  the  United 
States  from  Canada  south  to  Mexico  and  into  South  America. 


METHODS    OF    CONTROL. 

The  application  of  arsenical  and  contact  insecticides  are  of 
no  avail  against  this  insect.  Cultural  practices  must  be  relied 
upon  to  hold  it  in  check,  and  are  as  follows : — 

'    (i)   Plant  early  squashes  as  trap  crops  to  be  destroyed  later. 

(2)  Cut  out  the  borers  with  a  knife. 

(3)  Cover  the  vines  with  soil  to  induce  the  growth  of  new 

roots. 

(4)  Collect  and  burn  the  old  vines  as  soon  as  the  crop  is 

harvested. 

(5)  Crop  rotation. 

(i)  In  some  localities  growers  have  been  successful  in  planting 
early  varieties  such  as  crooknecks  between  the  rows  or  around 
the  margins  of  the  field.  The  moths  will  lay  their  eggs  on  these 
plants  which  can  later  be  pulled  up  and  burned.  The  main  crop 
appearing  later  will  escape  the  larger  part  of  the  infestation. 

(2)  Wherever  a  plant  has  become  infested,  a  careful  cut 
lengthwise  the  stem  with  a  small,  sharp  knife  will  disclose  the 
borer,  which  can  then  be  killed  with  the  knife.  A  careful 
examination  of  the  basal  portion  of  the  vine  will  disclose  the 
presence  of  a  borer,  as  the  yellow  frass  is  always  thrown  out 
through  a  hole  in  the  side  of  the  stem.  Such  an  examination 
should  be  made  early  in  July  and  repeated  several  times  during 
the  month  and  even  in  August.  If  the  vine  has  not  been  seriously 
injured  and  decay  has  not  set  in,  the  incision  will  heal. 

(3)  As  there  is  always  danger  that  a  borer  may  be  overlooked, 
each  vine  should  be  covered  with  soil  at  a  point  two  or  three 
feet  from  its  base  after  it  is  well  started  running  along  the 
ground.    New  roots  will  be  formed  at  this  point  and  even  if  decay 


42 


CONNECTICUT   EXPERIMENT    STATION    BULLETIN   2l6. 


wholly  destroys  the  stem  at  its  base  the  new  roots  enable  the 
plant  to  keep  on  and  mature  its  crop.  The  writer  has  seen  a 
squash  vine  yield  a  good  crop,  when  treated  in  this  way,  where 
the  main  stem  was  entirely  severed  from  its  root  system, 

(4)  As  the  moths  do  not  all  appear  at  the  same  time,  the  egg- 
laying  period  extends  over  a  long  time  or  perhaps  the  greater 
portion  of  the  summer.  Consequently,  larvae  may  be  present 
somewhere  in  the  vines  late  in  the  season.  Gathering  and  burn- 
ing the  vines  after  the  crop  has  been  harvested  will  destroy  many 
of  these  larvae  which  have  not  gone  into  the  ground  to  pupate. 

(5)  As  the  squash-vine  borer  hibernates  in  the  ground,  it  is 
advisable  not  to  grow  squashes  on  the  same  field  year  after  year. 


The  Squash  Lady-Beetle. 

Epilachna  borealis  Fabr. 

Though  nearly  all  of   the   lady-beetles   are  carnivorous   and 

therefore  beneficial  because  they  feed  upon  and  destroy  injurious 

insects  such  as  aphids  and  scale  insects,  there  is  one  exception  in 


Figure  10.  The  squash  lady-beetle:  a,  larva;  b,  pupa;  c,  adult  beetle, 
three  times  natural  size;  d,  egg,  four  times  natural  size;  e,  surface  of 
same  highly  magnified.  (After  Chittenden,  Bulletin  19,  Bureau  of  Ento- 
mology, U.  S.  Department  of  Agriculture.) 


Connecticut  in  the  squash  lady-beetle.  This  species  (both  adults 
and  larvae)  feeds  upon  the  leaves  of  cucurbitaceous  plants  but 
does  more  injury  to  squash  than  to  the  other  plants  of  this  group. 
The  adult  beetles  pass  the  winter  under  the  bark  of  dead  trees, 


PLATE  I. 


a.     Eggs,  as  laid  in  the  soil. 
Five  times  enlarged. 


b.     Striped  cucumber  beetle. 
Enlarged  four  times. 


c.    Work  of  the  striped  cucumber  beetle.     Natural  size. 
STRIPED  CUCUMBER  BEETLE. 


PLATE  II. 


Cucumber  plants  injured  by  the  larvae  of  the  striped  beetle. 
Natural  size. 


PLATE  III. 


X 


a.     Twelve-spotted   cucumber 
beetle.    Enlarged  four  times. 


b.     Eggs  of  squash-vine  borer. 


c.     View  at  farm  showing  protectors  over  cucumber  plants. 


PLATE  IV. 


SQUASH   BORER:    ADULT  AND  WORK  OF   LARVAE   IN   SQUASH   STEMS. 
Slightly  enlarged. 


PLATE  V. 


a.     A  field  of  healthy  squash  vines. 


b.     Vine  wilting  from  the  attacks  of  the  squash-vine  borer. 


PLATE  VI. 


c.     Squash  lady-beetle.     Twice  natural  size. 


b.     Larva  of   squash  lady-beetle.     Enlarged. 


c.     Work  of  the  squash  lady-beetle.     Greatly  reduced. 
SQUASH    LADY-BEETLE. 


PLATE  VII. 


a.     Squash  bug.     Twice  natural   size. 


b.     Eggs  and  young  squash  bugs.    All  natural  size. 


SQUASH    BUG. 


PLATE  VIII. 


a.     The  potato  aphid  on  squash  leaf.     Natural  size. 


b.     Greenhouse    white-fly.      Adults    and    pupa    skins.      Enlarged 
four  times. 


SQUASH   AND   CUCUMBER   INSECTS.  43 

stumps,  etc.,  or  other  sheltered  places,  emerging  in  June  and 
laying  their  eggs  on  the  under  surface  of  the  squash  leaves, 
These  hatch  in  about  twelve  days  and  the  larvae  begin  to  feed 
upon  the  under  side  of  the  leaves.  The  larvae  appear  in  Connect- 
icut about  the  middle  of  July  and  become  fully  grown  in  about 
three  weeks  or  early  in  August,  The  larva  is  about  three-eighths 
of  an  inch  in  length,  yellow,  with  six  rows  of  long  black  branched 
spines.  The  pupa  is  yellow  and  like  those  of  its  kind  is  attached 
by  the  tail  to  the  under  surface  of  the  leaf :  it  lasts  from  six  to 
nine  days.  There  is  only  one  generation  each  year.  All  stages 
of  this  insect  are  shown  in  figure  lo;  adults  and  larvae  on  plate 
VI. 

Though  the  larvae  are  found  feeding  upon  the  under  side  of 
a  leaf  in  July  and  August,  the  adults  are  generally  present  at  the 
same  time  as  well  as  earlier  and  later,  feeding  upon  the  upper 
surface.  The  adult  has  the  peculiar  habit  of  marking  out  with 
its  mandibles  a  definite  area  on  the  leaf,  and  then  feeding  within 
this  area.  This  form  of  injury  is  shown  on  plate  VI,  c.  The 
squash  lady-beetle  is  usually  a  minor  pest  being  present  only  in 
small  numbers;  handpicking  is  generally  the  best  method  of 
control  in  such  cases.  If  abundant  the  vines  should  be  sprayed 
with  lead  arsenate,  using  perhaps  two  pounds  of  the  paste  in 
fifty  gallons  of  water. 

Other  Chewing  Insects. 

Cutworms. — The  small  plants  are  often  eaten  off  by  cutworms, 
which  are  the  larvae  of  several  species  of  Noctuid  moths.  In 
small  plantations  these  can  be  hunted  and  crushed,  but  in  large 
fields  where  cutworms  are  destructive,  the  following  mash  should 
be  employed: — 

Wheat  bran  5  pounds 

Paris  green  or  white  arsenic  5  ounces 

Lemon  or  orange  i  fruit 

Molasses    i  pint 

Water   7  pints 

Mix  the  dry  poison  and  bran  together.  Squeeze  the  juice  from 
the  orange  or  lemon  into  the  water  and  also  add  the  pulp  and 
peel  cut  in  small  pieces :  then  add  the  molasses  and  stir.  Mix 
the  syrup  thoroughly  with  the  poisoned  bran.  This  will  make  a 
rather  dry  mash  which  may  be  scattered  thinly  over  the  field 


44  CONNECTICUT   EXPERIMENT    STATION    BULLETIN   2l6. 

at  the  time  when  the  injury  is  first  noticed.  As  the  cutworms 
feed  at  night,  the  mash  should  be  apphed  just  before  dark :  the 
cutworms  will  be  attracted  by  the  fresh  citrus  juice  and  molasses. 
If  allowed  to  become  dry  before  night,  it  will  have  lost  in  some 
measure  its  attraction  for  the  cutworms.  Late  fall  plowing  and 
very  thorough  harrowing  will  reduce  the  numbers  of  cutworms. 

Wireworms. — These  are  the  larvae  of  click  beetles  and  often 
are  so  abundant  as  to  injure  various  crops.  They  are  slender, 
hard,  cylindrical  grubs  usually  smooth  and  shiny  and  light  brown 
in  color.  They  injure  plants  by  tunneling  in  the  roots,  especially 
the  main  stem  below  the  surface  of  the  ground.  Crop  rotation, 
fall  plowing  and  thorough  harrowing  are  the  best  preventives. 

In  the  South,  the  pickle  worm  Diaphania  nitidalis  Stoll,  and 
the  melon  worm  Diaphania  hyalinata  Linn.,  cause  much  injury 
to  crops  of  melons,  cucumbers  and  squashes,  but  though  they 
occur  in  Connecticut,  they  are  rare  and  seldom  are  found  feeding 
upon  these  plants  in  cultivated  fields.  Planting  a  succession  of 
summer  squashes  at  intervals  of  two  weeks  as  trap  crops  seems 
to  be  the  best  method  of  controlling  these  insects. 

Certain  other  general  feeders  sometimes  attack  squashes  and 
cucumbers.  The  stalk  borer  Papaipema  nitela  Guen.  was  found 
by  the  writer  in  the  stem  of  a  melon  plant  in  1918.  Various 
caterpillars  of  the  families  Noctuidae  and  Arctiidae  occasionally 
feed  upon  the  blossoms,  leaves  or  young  fruit,  but  can  scarcely 
be  considered  as  pests  of  the  crop  in  Connecticut. 


SUCKING  INSECTS. 

The  Squash  Bug. 

Anasa  tristis  Degeer. 

The  squash  bug,   or    "stink  bug,"    is  an  important  pest  of 

squashes  and  pumpkins,   though  as  a   rule  it   does   not  injure 

cucumbers  and  melons  in  Connecticut.     It  injures  the  plants  by 

puncturing  the  tissues  of  a  vein  on  the  under  side  of  a  leaf, 

and  sucking  out  the  sap.    This  causes  the  leaf  to  wilt  badly  and 

die.    Frequently  all  the  leaves  on  a  vine  wilt  from  the  attacks  of 

these  bugs  and  the  entire  vine  dies. 

The  range  of  this  insect  covers  the  entire  United  States,  and 
is  from  Canada  to  Central  America.     The  adult  bugs  hibernate 


SQUASH    AND    CUCUMBER    INSECTS. 


45 


in  any  convenient  place  where  they  can  find  shelter,  such  as  in 
old  vines  and  rubbish,  under  loose  bark,  boards,  etc.,  and  emerge 
late  in  the  spring  and  attack  the  young  plants.  In  addition  to 
their  punctures   and  withdrawal   of   sap   from  the  plant,   it   is 


Figure  ii.  Eggs  of  squash  bug  as  they  are  laid  on  the  under  side  of  a 
leaf.  Enlarged.  (After  Chittenden,  Bulletin  19,  Bureau  of  Entomology, 
U.  S.  Department  of  Agriculture.) 


thought  that  some  poisonous  substance  is  injected  into  the  wound. 
A  few  punctures  are  sufficient  to  kill  a  small  plant. 

The  female  bugs  lay  on  the  under  side  of  the  leaves,  dark 
brown  shiny  eggs  in  clusters  containing  between  twenty  and 
forty  each,  arranged  in  more  or  less  regular  rows,  often  in  the 


Figure  12.  Nymphs  of  the  squash  bug;  different  stages,  about  twice 
natural  size.  (After  Chittenden,  Bulletin  19,  Bureau  of  Entomology, 
U.  S.  Department  of  Agriculture.) 


forks  of  veins,  as  shown  in  figure  11.  From  six  to  fifteen  days 
afterward,  these  eggs  hatch  and  the  young  nymphs  remain 
together  on  the  under  side  of  the  leaf  where  the  tgg  cluster  was 
laid.     They  are  at  first  green  with  pink  head,  legs  and  antennae, 


46  CONNECTICUT   EXPERIMENT   STATION    BULLETIN   2l6. 

but  after  the  first  molt,  they  are  ash-gray  in  color.  They  molt 
five  times  during  the  nymphal  period  of  four  or  five  weeks, 
during  which  they  are  sucking  the  sap  from  the  plants.  The 
nymphs  are  shown  in  figure  12,  and  on  plate  VII,  b. 

The  full-grown  bug  is  about  five-eighths  of  an  inch  long,  dark 
grayish-brown  in  color,  and  when  not  feeding  or  laying  eggs, 
the  adults  and  larger  nymphs  gather  round  the  base  of  the  plant 
or  under  clods  of  earth.  Frequently  they  congregate  on  the 
immature  fruits,  especially  where  the  foliage  has  been  killed 
by  frost  before  the  nymphs  reach  maturity.     There  is  only  one 


FiGUKE  13.  The  squash  bug:  a,  mature  female,  twice  natural  size;  b, 
side  view  of  head  showing  proboscis ;  c,  abdominal  segments  of  male ; 
d,  same  of  female.  Enlarged.  (After  Chittenden,  Bulletin  19,  Bureau  of 
Entomology,  U.  S.  Department  of  Agriculture.) 


generation  each  year.  Adults  are  shown  in  figure  13,  and  on 
plate  VII,  a,  and  the  beak  or  sucking  mouth  in  figure  14. 

In  the  South  there  are  two  other  species  of  this  genus  which 
are  associated  with  the  squash  bug  and  cause  similar  injury  to  the 
plants  though  less  abundant.  In  the  southern  states,  the  south- 
ern leaf-footed  plant  bug  Leptoglossus  phyllopus  Linn,  injures 
melons  and  various  other  vegetable  crops,  and  in  the  central 
states,  the  northern  leaf-footed  plant  bug  Leptoglossus  oppo- 
situs  Say,  occasionally  attacks  cucurbitaceous  plants,  but  these 
insects  have  not  been  recorded  from  Connecticut. 

Methods  of  Control. — The  adults  are  hard  to  kill  and  such 
methods  as  the  burning  of  all  old  vines  and  rubbish  around  the 


SQUASH    AND    CUCUMBER    INSECTS. 


47 


field,  trapping  under  boards  and  handpicking  are  the  means  of 
destroying  them.  Egg-masses  on  the  leaves  may  be  crushed,  or 
scraped  off  with  the  edge  of  a  knife.  The  nymphs,  especially  the 
younger  ones,  may  be  killed  by  spraying  with  kerosene  emulsion, 


Figure  14.     Squash  bug.    Enlarged  view  showing  head  and  proboscis. 

or  with  nicotine  solution,  two  teaspoonfuls  in  a  gallon  of  water, 
to  which  an  inch  cube  of  laundry  soap  has  been  dissolved  and 
added.  In  applying  any  spray  to  kill  the  nymphs,  it  is  necessary 
to  use  an  upturned  nozzle  in  order  to  direct  the  spray  against 
them  on  the  under  side  of  the  leaves. 


The  Melon  Aphid. 
Aphis  gossypii  Glover. 
This  is  one  of  the  most  troublesome  insect  pests  of  cucumbers 
and  melons  throughout  its  range  over  the  eastern  half  of  the 
United  States  and  southward  into  Brazil.  In  Connecticut  it  is 
present  in  nearly  every  field  of  cucumbers  and  melons,  and  being 
on  the  under  side  of  the  leaves,  it  escapes  notice  until  the  leaves 
begin  to  curl  on  account  of  its  attacks.  It  is  much  less  trouble- 
some on  squashes  and  pumpkins,  but  has  a  long  list  of  food 
plants,  including  many  of  our  common  vegetables,  and  cotton  in 
the  South.  It  is  apparently  able  to  subsist  on  a  large  number  of 
common  weeds,  though  its  complete  life  history  is  still  unknown. 
Whether  it  produces  winter  eggs,  or  each  year  migrates  from  the 
South,  or  lives  over  in  greenhouses  is  still  a  matter  for  specula- 


48 


CONNECTICUT   EXPERIMENT   STATION    BULLETIN   2l6. 


tion.  It  is  able  to  multiply  so  rapidly  that  plants  are  often 
injured  in  a  short  time.  The  infested  leaves  curl  backward  or 
downward,  making  it  very  difficult  to  reach  the  aphids  with  a 
spray.  The  melon  aphid  is  shown  in  figure  15.  It  is  preyed 
upon  by  our  common  lady-beetles,  larvae  of  syrphid  flies,  lace- 


FiGURE  15.  The  melon  aphis:  a,  winged  female;  aa,  enlarged  antenna 
of  same;  ab,  dark  form,  side  view;  b,  young  nymph;  c,  last  stage  of 
nymph;  d,  wingless  female.  All  greatly  enlarged.  (After  Chittenden, 
Circular  80,  Bureau  of  Entomology,  U.  S.  Department  of  Agriculture.) 


wing  flies,  and  several  species  of  parasitic  four-winged  flies  aid 
in  holding  it  in  check. 

Control. — In  small  gardens  the  vines  can  be  watched  and  when 
the  aphids  first  appear,  the  vines  should  be  sprayed  or  fumigated 
to  kill  them.  For  fumigating,  covers  can  be  made  by  stretching 
table  oilcloth  over  light  wood  frames.  Each  frame  should  be 
large  enough  to  cover  a  hill,  and  either  carbon  disulphide  (bisul- 
phide) one  teaspoonful  to  each  cubic  foot  of  space,  or  tobacco 
fumes  may  be  employed  as  a  fumigant.     The  former  should  be 


SQUASH    AND    CUCUMBER    INSECTS.  49 

placed  in  a  shallow  dish  or  saucer  under  the  cover.  Tobacco 
fumes  may  be  obtained  by  burning  tobacco  stems,  or  some  prep- 
aration of  nicotine  and  paper. 

In  spraying,  either  kerosene  emulsion  or  nicotine  solution  may 
be  used,  and  the  nozzle  should  be  upturned  by  using  a  rod  bent 
near  the  nozzle.  The  spraying  operation  will  be  facilitated  by 
training  all  vines  to  run  along  the  rows  instead  of  across  them. 

If  nicotine  solution  is  used,  it  should  be  in  the  proportions  of 
one-half  pint  of  "Black  Leaf  40"  in  fifty  gallons  of  water,  to 
which  about  three  pounds  of  laundry  soap  has  been  dissolved  and 
added. 

Kerosene  emulsion  may  be  prepared  as  follows 

Laundry  soap   (about  30  oz.)    3  cakes 

Kerosene   3  gallons 

Water 2  gallons 

After  churning,  dilute  eight  times  to  make  one  barrel  (50 
gallons.) 

The  soap  should  be  cut  into  thin  slices  and  dissolved  in  hot 
water  over  a  fire.  Then  remove  from  the  fire,  add  the  kerosene 
and  churn  vigorously  for  a  few  moments  by  passing  the  liquid 
through  a  spray  pump  having  a  small  opening  in  the  nozzle,  and 
the  stream  directed  back  into  the  container.  This  makes  a  uni- 
form creamy  mass  from  which  the  oil  does  not  separate  on  stand- 
ing. Then  dilute  with  the  necessary  amount  of  water  and  spray 
against  the  under  surface  of  the  leaves. 

In  all  spraying  operations  a  good  pressure  should  be  main- 
tained, and  a  fine  nozzle  used.  In  commercial  plantations,  some- 
times the  first  plants  found  to  be  infested  are  pulled  up  and 
buried  or  burned  to  kill  the  aphids.  Dusting  with  insect  powder 
or  fine  tobacco  dust  applied  with  a  powder  gun  is  also  practiced 
in  some  cases.  In  any  event,  the  treatment  should  be  given 
before  the  leaves  have  curled  as  it  is  difficult  afterward  to  hit  the 
aphids. 

The  Squash  Aphid. 
Macrosiphum  cucurbitae  Middleton. 
This  is  a  light  green  aphid,  considerably  larger  than  the  melon 
aphid,  but  is  never  as  abundant  and  therefore  never  as  destruc- 
tive as  that  species. 


50  CONNECTICUT   EXPERIMENT   STATION    BULLETIN   2 1 6. 

The  Potato  Aphid,  Macrosiphum  solanifolii  Ashtn.,  was  found 
on  squash  at  the  Station  in  1909  and  again  in  1914.  It  is  shown 
on  plate  VIII,  a. 

Both  the  aphids  mentioned  above,  if  sufficiently  abundant  to 
warrant  the  outlay,  may  be  controlled  by  the  same  methods 
advised  for  the  melon  aphid. 

The  Greenhouse  White-Fly. 
Asterochiton  (Aleyrodes)  vaporariorum  Westwood. 
Cucurbits  growing  under  glass  or  out  of  doors  near  green- 
houses are  often  attacked  and  considerably  injured  by  the  green- 
house white^fly.  The  white  moth-like  adults  are  found  resting 
on  the  under  sides  of  the  leaves  where  they  lay  eggs  and  where 
the  nymphs  also  occur.  The  eggs  are  very  small,  ovate,  whitish, 
and  are  attached  to  the  leaf  by  a  short  stalk  at  the  larger  end. 
The  nymphs  are  oval,  flat,  light  green,  and  -resemble  scale- 
insects.  The  empty  pupa  skins  are  silvery  white  and  adhere  for 
a  long  time  to  the  leaf.  The  adults  are  pure  white  and  in  appear- 
ance look  as  if  sprinkled  with  flour.  This  insect  is  shown  on 
plate  VIII,  b,  but  a  more  detailed  description  may  be  found  in  the 
Reports  of  this  Station  for  1902,  page  148,  and  for  1906,  page 

275- 

The  same  treatment  recommended  for  the  melon  aphid  will 

control  the  greenhouse  white-fly.  Spraying  with  soap  and  water 
(common  laundry  soap,  one  pound  dissolved  in  eight  gallons)  is 
also  effective. 

In  greenhouses  it  is  often  advisable  to  fumigate  the  entire 
house  with  hydrocyanic  acid  gas,  using  one-half  ounce  of  cyanide 
for  each  thousand  cubic  feet  of  space  with  an  exposure  of  three 
hours.  This  is  by  far  the  most  effective  of  all  treatments.  If 
spraying  is  depended  upon  to  hold  the  pest  in  check  it  must  be 
repeated  frequently. 

Summary. 

Chewing  insects  which  attack  and  injure  squash,  pumpkin, 
cucumber  and  melon  plants  in  Connecticut  are  the  striped  cucum- 
ber beetle,  the  squash-vine  borer,  and  occasionally  the  twelve- 
spotted  cucumber  beetle,  the  cucumber  flea  beetle,  the  garden 
flea  or  springtail,  the  squash  lady-beetle,  cutworms  and  wire- 


SQUASH    AND    CUCUMBER    INSECTS.  5 1 

worms.  The  striped  and  twelve-spotted  beetles  can  be  controlled 
by  covering  the  plants  with  netting,  or  by  spraying  or  dusting 
them  with  lead  arsenate.  The  cucumber  flea-beetle  and  the 
squash  lady-beetle  may  likewise  be  controlled  with  lead  arsenate. 

To  control  the  squash-vine  borer,  plant  early  squashes  as  a  trap 
crop  to  be  destroyed  later :  cut  out  the  borers  with  a  knife :  cover 
the  stems  of  the  vines  with  soil  to  induce  the  formation  of  new 
roots :  collect  and  burn  all  the  old  vines  as  soon  as  the  crop  is 
harvested.  Cutworms  can  best  be  controlled  by  the  use  of  a 
poisoned  bran  mash,  and  wireworms  by  fall  plowing  and  rota- 
tion of  crops. 

The  most  troublesome  sucking  insects  on  cucurbits  in  Connect- 
icut are  the  squash  bug  and  the  melon  aphid.  Minor  pests  of 
this  nature  are  the  squash  aphid,  potato  aphid,  and  greenhouse 
white-fly.  All  of  these  pests  can  be  controlled  by  spraying  at  the 
right  time  with  nicotine  solution  and  soap,  with  kerosene  emul- 
sion, or  by  fumigating. 

Gathering  and  burning  the  old  vines  and  other  rubbish  on  the 
field  after  the  crop  has  been  harvested  is  a  worthy  practice  and 
will  tend  to  reduce  the  numbers  of  all  insects  attacking  the  crop. 

Rotation  of  'crops  should  also  be  practiced,  where  possible. 

Information  concerning  each  of  these  pests  and  how  to  con- 
trol them  is  given  in  the  foregoing  pages,  and  most  of  them  are 
shown  on  plates  I-VIII. 


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